Voltage-gated potassium channels are critical for neuronal function. There are estimated 160 genes encoding different but highly homologous potassium channels in humans. Because of the considerable sequence homology, gene-specific channel modulators are very rare but they are sought-after reagents both for investigating channel function and developing therapeutics. The KCNQ (or Kv7) channel family includes five members: KCNQ1 to KCNQ5. Evidence from patient studies and animal models has shown that a small change in KCNQ expression by as little as 25% can cause disease conditions such as epilepsy. Therefore, chemical probes would be powerful analytical tools to investigate the structure and function of voltage-gated potassium channels, and in the case of KCNQ, these compounds may be very valuable for therapeutic development. To perform a large-scale compound screen, KCNQ channel cell lines have been generated and an HTS-ready protocol has been developed and optimized. The present application seeks to conduct a large scale compound screen using the developed assay. The specific aims of the proposal are: 1. To effectively work with the NIH-assigned MLPCN center to perform a large compound library (>100,000 compounds) and validate lead compounds that specifically ACTIVATE the heteromultimeric KCNQ2/3 potassium channel 2. To conduct the secondary assays and counter screen against KCNQ1, 4 and 5. 3. To perform initial characterization to allow for selection of potent lead compounds for detail functional analyses. The success of this project will lead to identification of novel compounds that are useful for developing therapeutics and investigating M-current and KCNQ ion channel function. PUBLIC HEALTH RELEVANCE: Small molecules that regulate ion flux are important tools to develop drugs to treat brain and heart diseases. They are also useful research probes to understand structure and function of ion channel proteins which mediate membrane ionic flux. This proposal is aimed at carrying out a screen of large compound library in an effort of finding novel chemical modulators for ion channels.